As you can see in the example below we have the two "fixed size" images that allow the viewer to see what their avatar will look like (the smaller 60x60 is used on the chat pages and the 90x90 is used on the profile popup).

The user can select the "location" they want to use and the quasi "zoom" is handled by them dropping and dragging the selector box.

Really pretty easy actually.

We'll be rolling this out to all of the http://www.livefanchat.com/ sites over the next few days after some further testing but if you find it useful be sure to thank the original developer.